Apparatus for cutting multiple tubular conduits



Jan. 3, 1967 B, J, CORDARY ETAL 3,295,604

APPARATUS FOR CUTTING MULTIPLE TUBULAR CONDUITS Filed July 10, 1964 5 Sheets-Sheet l 2; 1 BZW// Jan 3, 1967 B. J. CORDARY ETAL 3,295,604

APPARATUS FOR CUTTING MULTIPLE TUBULAR CONDUITS Filed July 10, 1964 5 Sheets-Sheet 2 Jan. 3, 1967 B. J. coRDARY ETAL 3,295,604

APPARATUS FOR CUTTING MULTIPLE TUBULAR CONDUITS 5 Sheets-Sheet 5 Filed July l0, 1964 INVENTORS.

United States Patent O 3,295,604 APPARATUS FOR CUTTING MULTIPLE TUBULAR CONDUITS Bruce I. Cordary, Los Alamitos, and Robert W. Weber, Long Beach, Calif., assignors to The Servco Company, Long Beach, Calif., a corporation of Nevada Filed July 10, 1964, Ser. No. 381,722 4 Claims. (Cl. 166--55.8)

The present invention relates to an apparatus for cutting tubular conduits disposed in well bores and, more particularly, to an apparatus for cutting a plurality of tubular conduits in a well bore.

In the production of oil from subsurface formations, multiple completions are frequently employed. Such completions sometimes require two or more casing strings of gradually diminishing diameters and are utilized to produce oil from strata at different depths. After landing of multiple casing strings, subsequent remedial work, production problems, or casing salvage operations may necessitate cutting each of the concentrically disposed casing strings to sever them, or cutting and milling of sections in each.

The present invention provides a tool which is capable of cutting within a well bore a smaller diameter inner tubular conduit and then sequentially cutting one or more larger diameter outer tubular conduits at substantially the same vertical level. The apparatus of the present invention comprises a tubular tool body within which a iirst piston is disposed to move within a bore in the tool body. The first piston has a surface exposed to uid pressure in the tool body bore. A second piston has a surface exposed to the same fluid pressure. The cross-sectional area of the surface of one piston is smaller than the crosssectional area of the surface of the other piston. At least one cutter is pivotally joined at one of its ends to the tubular body. Interconnecting means are hingeably secured at opposite ends to engage the other end of the cutter and one of the two pistons. The other of the two pistons is provided with means to engage the interconnecting means upon movement of the other piston and thereby to move the cutter outwardly toward the inner tubular conduit. Stop means are provided to stop movement of the other piston'after outward movement of the cutter is initiated. A passageway in the tool body provides fluid communication between a source of pressure and the one end of the bore. When pressure is applied to the uid, a. greater total force is applied to the piston having the larger cross-sectional area. Movement of this piston in the direction of the stop means occurs without significant movement of the other piston; When the piston having the larger cross-sectional area is moved to the stop means, the fluid pressure acts to move both pistons as a unit.

In a presently preferred embodiment of the invention, the interconnecting means and the cutter are in a substantially columnar array prior to movement of the pistons. The interconnecting means is joined to a first piston having the smaller cross-sectional area. The wedging or camming action against the interconnecting means produced by movement of the second piston, which has the larger cross-sectional area, not only moves the cutter outwardly but also displaces the hinged interconnecting means to position it whereby a compressive force can be exerted by movement of the iirst piston. When, thereafter, both pistons move as a unit, the lirst piston acts through the interconnecting means to force the cutter outwardly to an extent corresponding to the length of piston movement.

The apparatus of the present invention may be utilized to sequentially cut through a variety of sizes of casings. As an example of its utility, it may be used to cut initially through a 9%" inner casing and then to cut through an Patented Jan. 3, 1967 ICC outer casing having a diameter as large as 26". One or more larger diameter outer casings may be cut and milled after the cutter has cut and milled the smallest diameter casing in the well bore,

Theapparatus of the present invention and its operation will be better understood from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary sectional elevation of the apparatus -of the present invention showing a cutter in the retracted position .in which the apparatus is lowered down the well bore;

FIG. 2 is a fragmentary sectional elevation of the apparatus of FIG. 1 showing the cutter actuated to cut through a smaller inner tubular conduit or casing; and

FIG. 3 is a sectional elevation showing the apparatus of FIG. 1 showing the cutter actuated to cut through a larger outer tubular conduit or casing.

With reference to FIG. 1, the operative elements of the apparatus of the present invention are shown in a tubular tool body 10 positioned within a smaller diameter inner casing 12 and a concentric larger diameter outer casing 14. While the apparatus is described with reference to two casings, it will be understood that it can be used to cut and mill additional casings which are intermediate casings 12 and 14 in diameter. Although not shown, the upper end of the tool body has a conventional threaded pin by which it is connected to the lower end of a string of tubular drill pipe.

Tool body 10 has an axial central bore 16 consisting of three differing diameters. The diameters progressively increase in passing from the uppermost to the lowermost portions of the bore. For convenience of description, the lowermost portion is referred to herein as lower bore 18, the intermediate portion as intermediate bore 20, and the uppermost portion as upper bore 22. A shoulder 24 is formed between lower bore 18 and intermediate bore 20.

A rst piston 26 disposed within bore 16 includes a lower section 28 having a diameter for slidable movement within lower bore 18 and an upper section 30 having a diameter for slidable movement within intermediate bore 20. Piston sealing rings 32 are provided in the lower section of the iirst piston. A shoulder 34 is formed where the upper section of the piston meets the lower section.

A chamber 36 of three differing diameters is formed to extend centrally through the first piston and consists of lower chamber 38, intermediate chamber 40 and upper chamber 42. The diameters progressively increase in passing from the upper chamber to the lower chamber. A shoulder 44 is formed between intermediate chamber 40 and lower chamber 38, and a shoulder 46 is formed between intermediate chamber 4t! and upper chamber 42. A second piston 48 disposed in chamber 36 has a diameter for slidable movement within lower chamber 38. A snap ring 50 is inserted in the lower end of the wall dening the lower chamber to limit downward movement of the second piston. The second piston includes a stinger 52 joined to its upper face. The diameter of the stinger enables slidable movement within upper chamber 42 and upper bore 22. Preferably, the upper end of the stinger is formed in the shape of a truncated cone to provide the wedging or camming action to be described. A` spring 54 is biased between shoulder 46 and the upper face of the second piston.

A strut 56 is hingeably mounted at one end of a pin l 5S secured to the upper section of the rst piston. The

' position, strut 56 and cutter 64 are aligned in a substantially columnar array. The other end of the cutter is hingeably mounted on a pin 66 which is fitted in the tool body. The other end of the cutter is rounded to lit within a curved recess in a lug 67 joined to the body by a lug retaining screw 67a. Cutter 64 is accommodated within an opening 68 formed in the tool body. While not shown, cutter 64 is faced with a hard-facing material such as tungsten carbide along its side edge 70 and its bottom edge 72. While only one cutter is shown in the drawing, it will be understood that a plurality of cutters, interconnected to the first piston by struts in the same manner as already described with refeernce to strut 56 and cutter 64, are conventionally employed. Typically, three cutters are utilized.

Vertical flow passages, of which one passage 74 is shown in the drawings, extend downwardly through the tool body-and provide tlow communication between the Vlower end of lower -bore 1S and an upper central passage 76. Passage 76 opens at its upper end into the tubular drill string previously described so that lower bore 18 is in fluid ow communication with a source of uid pressure at the surface of `the well.

`A bottom passage 78 is connected by a flow restricting opening or orifice 80 to open into the lower end of lower bore 1'8. Although not shown in the drawing, the bottom end of the tool body is open so that fluid ows successively through passages 76 and-74 into the lower end of lower bore 18. |From the lower bore, it passes through opening 80 into bottom passage 78 and out of the open Ibottom end of the tool. The fluid then flows upwardly in the annular space lbetween the tool body and the casings.

The operation of the apparatus of the present invention will now be described with reference to FIGS. l, 2 and 3, the elements identified 'by reference characters in theV opening 80 creates a back pressure which produces aV higher pressure on `the lower faces of the first and second pistons than is found above the pistons. The only uid in the bores above the piston is that which leaks in around the strut. The only pressure on this fluid is the hydrostatic head of the uid column in the annularV spaces between the tool body and the casings. Since the second piston has a larger cross-sectional area than the first piston, a greater total force is exerted upon the second piston. Asa result, upward 4movement of second piston 48 occurs with little,rif any movement of the first piston.

The upward movement of the second piston and its stinger lboth compresses spring 54 and causes the upper end of the stinger to engage cam surface 60 of strut 56. The camming or wedging action provided by the stinger displaces the strut from its vertical position and forces it outwardly -with resultant outward movement of the cutter to engage the inner casing. Upon rotation the hard facing on the cutter cuts through the casing and mills Vout a section. The cutters are lubricatedrby the fluid tlowing through the annular spaces as previously described. As shown in FIG. 2, the cutter has cut through and milled a section or window in the inner casing before further upward movement of the second piston is stopped by shoulder 44. It is to be understood, however, thatthe only wedging orcarnming action required is that neces.- sary to displace the strut from its vertical position to enable exertion of a compressive force by upward movement of the first piston. Accordingly, the apparatus can 4 be made so that, once the strut is displaced by the stinger from its substantially columnar array with the cutter, further upward movement of the second pis/ton is stopped.

When upward movement of the second piston is halted by shoulder 44 as shown in FIG. 2, the huid pressure acts rupon the surfaces of the second piston and the iirst piston as a unit.l As a result, both the first piston and the second piston move upwardly as a unit so that cutter 64 is forced further outwardly by the compressive force exerted through the strut by the movement of the piston. The upward movement of the piston assembly is continued until the cutter cuts through aud mills the lar-gest diameter conduit in the well bore. A section or window 82 cut through the inner casing enables pivotal movement of the cutter to the position shown in FIG. 3. Shoulder 34 on the first piston engages shoulder 24 of the tool body so as to stop further upward movement of the piston assembly, as particularly shown in FIG. 3.

In order to return the tool to the position shown in FIG. 1, the surface pump is stopped and the tlid pressure is removed. Spring 54, which had been compressed by `the upward movement of the second piston, thereupon returns the second .piston to the position shown in FIG. 1. Downward movement of the second piston is limited by snap ring 50 in the lower chamber. is returned to its initial position, a space is provided for return ofrstrut 56 and cutter 64 to the position shown in FIG. 1. This is accomplished by raising the tool so that the uncut portions of the casings force the cutters inwardly to the initial position.

The apparatus of the present invention provides a conipact tool which enables cutting through a series of casinfgs or tubular conduits with one set of cuttersv and by one trip yof `the drill string into the well bore. As a result, there is no necessity for removing the drill string Y from the hole to change the cutter tool.

Y within the scope of the invention to achieve the purposes Y Although the invention has been described with reference to the rspecific embodiment shown in FIGS. 1-3, it will be understood that this description has been for the purpose of illustration and that variations may be made herein described.

We claim:

1. An apparatus for sequentially cutting an inner tubular conduit and at least one larger outer tubular conduit disposed in a Well bore comprising:

(a) a tool body adapted to be secured Vto a drill string and having an axial bore;

(b) yone piston reciprocably and slidably movable within the bore in the tool body and having a surface exposed to'ruid pressure in the bore; (c) a second piston having a surface exposed to the same uid pressure;

(i) the cross-sectional area of said surface of the iirst piston being smaller than the cross` sectional area of said surface of the second piston;

(d) at least one cutter pivotally joined at one of the ends to the tubular body;

(e) innterconnecting means hingeably secured at its opposite ends to the other end of the cutter and to one of the two pistons;

(t) means on the other of the two pistons for engaging' the interconnecting means upon movement of said other piston and thereby to move the cutter outwardly toward the inner tubular conduit;

(g) stop means to stop movement of said other piston Y after outward movement of the cutter is initiated;

and

(h) a passageway providing huid communication between a source of pressure and the -bore whereby application of liuid pressure moves said other piston to the stop means and thereupon moves the first and second pistons as a unit.

Since the second piston 2. An apparatus for sequentially cutting an inner tubular conduit and at least one larger outer tubular conduit disposed in a well bore comprising:

(a) a tool body adapted to be secured to a drill string and having an axial bore; t

(b) a iirst piston reciprocably and slidably movable within the bore in the tool body,

(i) the iirst piston having a chamber opening into one end of the Ibore in the tool body;

(c) a second piston reciprocably and slidably movable within the chamber,

y(i) the cross-sectional area of the iirst piston facing the one end of the bore of the tool body being smaller than the cross-sectional area of the second piston facing said end;

(d) at least one cutter pivotally joined at one of the ends to the tubular body;

(e) interconnecting means hingeably secured at its opposite ends to the other end of the outter and the first piston, respectively;

(f) means on the second piston for engaging the interconnecting means upon movement of the second piston and thereby to move the cutter outwardly toward the inner tubular conduit;

('g) stop means within the chamber to stop movement of the second piston after outward movement of the cutter is initiated; and

(l1) a passageway providing uid communication between a source of pressure and the one end of the bore whereby application `of pressure on the fluid moves the second piston to the stop means and thereupon moves the rst and second pistons as a unit.

3. An apparatus for sequentially cutting an inner tubular conduit and at least one larger ofuter conduit disposed in a well bore comprising:

(a) a tool body adapted to be secured to a drill string and having an axial bore;

(b) a tirst piston rcciprocably and slidably movable Within the bore in the tool body,

(i) the-tirst piston having a chamber opening into one end of the bore in the tool body;

(c) a second piston reciprocably and slidably movable within the chamber,

(i) the cross-sectional area of the first piston facing the one end of the bore of the tool body being smaller than the cross-sectional area of the second piston facing said end;

(d) a plurality of cutters, each being pivotally joined at one of the ends to the tubular body;

(e) a strut hingeably secured at yits opposite ends to the other end of each cutter and the -rst piston, respectively;

(i) each strut and its associated cutter being aligned in a substantially columnar array when the cutter is in a retracted position;

(f) means on the second piston for engaging each strut upon movement of the second piston and thereby to displace the strut from its columnar array 'with the cutter and to move the cutter outwardly toward the inner tubular conduit;

(g) stop means within .the chamber .to stop movement of the second piston after outward movement of the cutter is initiated; and

(h) a passageway providing iluid communication between a source of pressure and the one end of the bore whereby application of pressure on the uid moves the second piston to the stop means and thereupon moves the iirst and second pistons as a uni-t.

4. An apparatus for sequentially cutting and milling an inner tubular conduit and at least one larger outer tubular conduit disposed in a well bore comprising:

(a) a tool body adapted to be secured to a drill string and having an axial bore;

(b) a iirst piston reciprocably and slidably movable within the bore in the tool body,

(i) the first piston having a chamber opening into one end of the bore in the tool body;

(c) a second piston reciprocably and slidably movable within the chamber,

(i) the cross-sectional area of the =iirst piston facing the one end of the bore of the tool body being smaller than the cross-sectional area of the second piston facing said end;

(d) a plurality of cutters, each being pivotally joined at one of its ends to the tubular body;

(e) a strut hingeably secured at its opposite ends to the other end of each cutter and the rst piston, respectively;

(i) each strut and its associated cutter being aligned in a substantially columnar array when the cutter is in a retracted position;

(ii) each strut including a cam surface extending into the bore near its other end;

(f) means on the second piston for engaging the cam surface of each strut upon movement of the second piston and thereby to displace the strut from its columnar array with the cutter and to move the cutter outwardly toward the inner tubular conduit;

(g) stop means within the chamber to stop movement of the second piston after outward movement of the cutter is initiated; and

(h) a passageway providing [duid communication between a source of pressure and the one end of the bore whereby application of pressure on the fluid moves the second piston to the stop means and thereupon moves the tirst and second pistons as a unit,

(i) the movement of the irst piston acting through the strut to urge the cutter further outwardly to engage a layer outer tubular conduit.

References Cited by the Examiner UNITED STATES PATENTS 2,35 3,284 7/ 1944 Barre-tt 166-55 .8 2,735,485 2/ 1956 Metcalf 166-55.8 2,743,906 5/ 1956 Coyle 175-269 CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner. 

1. AN APPARATUS FOR SEQUENTIALLY CUTTING AN INNER TUBULAR CONDUIT AND AT LEAST ONE LARGER OUTER TUBULAR CONDUIT DISPOSED IN A WELL BORE COMPRISING: (A) A TOOL BODY ADAPTED TO BE SECURED TO A DRILL STRING AND HAVING AN AXIAL BORE; (B) ONE PISTON RECIPROCABLY AND SLIDABLY MOVABLE WITHIN THE BORE IN THE TOOL BODY AND HAVING A SURFACE EXPOSED TO FLUID PRESSURE IN THE BORE; (C) A SECOND PISTON HAVING A SURFACE EXPOSED TO THE SAME FLUID PRESSURE; (I) THE CROSS-SECTIONAL AREA OF SAID SURFACE OF THE FIRST PISTON BEING SMALLER THAN THE CROSSSECTIONAL AREA OF SAID SURFACE OF THE SECOND PISTON; (D) AT LEAST ONE CUTTER PIVOTALLY JOINED AT ONE OF THE ENDS TO THE TUBULAR BODY; (E) INNTERCONNECTING MEANS HINGEABLY SECURED AT ITS OPPOSITE ENDS TO THE OTHER END OF THE CUTTER AND TO ONE OF THE TWO PISTONS; (F) MEANS ON THE OTHER OF THE TWO PISTONS FOR ENGAGING THE INTERCONNECTING MEANS UPON MOVEMENT OF SAID OTHER PISTON AND THEREBY TO MOVE THE CUTTER OUTWARDLY TOWARD THE INNER TUBULAR CONDUIT; 